Shampoo compositions are available that are effective in cleansing the hair, provide copious lather, and have a creamy, lubricated feel. These compositions, which are available on the retail market, often employ as the primary surfactant a water-soluble salt of lauryl sulfate. Other detergents including the water-soluble salts of lauryl ethoxysulfate are also used as the primary or secondary surfactant.
In addition to water and these anionic surfactants, good shampoos invariably contain coco diethanolamide or lauroyl diethanolamide, which act both to stabilize the foam and to increase the viscosity of the composition. Often a small amount of an inorganic salt is added. This assists the diethanolamide in further increasing the viscosity, A water-soluble gum, particularly a cellulosic gum, may also be used to increase the viscosity. The viscosity of a shampoo should not be too low, otherwise the shampoo is likely to drip from the hair into the eyes.
Ancillary agents may include protein hydrolysates and fatty esters as hair conditioning agents. Preservatives, color and fragrance are also used.
In the past, conventional shampoos have been compounded with normally gaseous, liquified hydrocarbons or fluorocarbons, generally at vapor pressures in the range of 25 to 40 psig. These pressurized compositions delivered a pre-formed shampoo lather. However, there appeared not to be any benefit in the use of these products and they were not successful.